Fix multiple reflection/documentation disparities

[Majkl578]

Multiple reflection or documentation disparities fixed:

• ssh2_connect
  • added missing parameters
  • only first parameter is required
• ssh2_disconnect
  • renamed reflection parameter according to doc & other functions
• ssh2_methods_negotiated
  • renamed reflection parameter according to doc & other functions
• ssh2_fingerprint
  • renamed reflection parameter according to doc & other functions
  • second parameter is optional
• ssh2_scp_send
  • swap parameters according to docs
• ssh2_fetch_stream
  • rename reflection parameter according to docs
• ssh2_sftp_mkdir
  • sync parameter & variable name according to docs
• ssh2_sftp_rmdir
  • sync parameter & variable name according to docs

[langemeijer]

Thank you for your contribution.